What's so awesome about putting together an outfit for a rave party is that you can find a lot of used clothing that works out well and there are a ton of stores that cater to the used clothing market. There is a store in the town I live that receives 5000 used items a day and its so busy in there I'm sure they are selling it just as fast as it comes in.

Another bonus with the type of clothes you want for a rave is that they are usually baggy and comfortable. Seriously - you are going to need big pockets to hide stuff in.

Its tricky to find stores that cater to ravers unless you live in an urban center. I would recommend just hunting around everywhere like auction sites to find that prime piece for your outfit.